Without knowing the schema you have built...
Create a table for Technicians that contains technician attributes (fname,lname etc)
Table for technician workdays that contains the date and the on-duty technician id.
If Job card table has a work to be performed date that can be related to the technician workdays table and get the technician id.
thanks for the reply
But what do i use so that technicians are automatically rotated after 24 hours.
for a precise solutions you need to give up more details...
Without knowing the specifics of the schema we can only provide vague suggestions that may or may not actually work with what you have already done.
Can you post the file?
I will play around with it